Role of the Appendicitis Inflammatory Response (Air) Score in the Early Diagnosis of Acute Appendicitis

Abstract

Background: Acute appendicitis is one of the most common surgical emergencies worldwide and remains a significant diagnostic challenge because of its variable clinical presentation. Delayed diagnosis may result in complications such as perforation and peritonitis, whereas overdiagnosis can lead to unnecessary appendectomies. The Appendicitis Inflammatory Response (AIR) score is a clinical scoring system that combines symptoms, signs, and inflammatory markers to improve diagnostic accuracy and assist in clinical decision-making.

Aim: To evaluate the role of the Appendicitis Inflammatory Response (AIR) score in the early diagnosis of acute appendicitis and assess its impact on imaging utilization and emergency department management.

Materials and Methods: This prospective observational study was conducted in the Institute of General Surgery, Rajiv Gandhi Government General Hospital, Chennai, over a period of one year. A total of 120 patients aged 16 years and above presenting with suspected acute appendicitis were included. AIR scores were calculated using clinical parameters and laboratory investigations, including white blood cell count, neutrophil percentage, and C-reactive protein levels. Patients were categorized into low-risk (0–4), intermediate-risk (5–8), and high-risk (≥9) groups. Final diagnosis was established by histopathological examination in operated patients and clinical follow-up in non-operated patients. Diagnostic performance parameters including sensitivity, specificity, positive predictive value, and negative predictive value were analyzed.

Results: The study included 64 females (53.3%) and 56 males (46.7%), with a mean age of 42.3 ± 18.7 years. The mean AIR score was 6.2 ± 2.1. Based on risk stratification, 27 patients (22.5%) were classified as low risk, 80 (66.7%) as intermediate risk, and 13 (10.8%) as high risk. Acute appendicitis was confirmed in 95 patients (79.2%), including 55 cases (45.8%) of uncomplicated appendicitis and 40 cases (33.3%) of complicated appendicitis. At a cutoff score of ≥5, the AIR score demonstrated a sensitivity of 96% and specificity of 76% for diagnosing acute appendicitis. Computed tomography was required in only 35 patients (29.2%), and the negative appendectomy rate was 4.2%. The mean emergency department length of stay was 5.8 ± 2.4 hours, with a significant association between AIR score category and duration of stay (p < 0.001).

Conclusion: The Appendicitis Inflammatory Response score is an effective and reliable tool for the early diagnosis of acute appendicitis. It provides excellent diagnostic accuracy, facilitates risk stratification, reduces unnecessary CT imaging, improves emergency department efficiency, and minimizes negative appendectomy rates. Routine incorporation of the AIR score into clinical practice may enhance patient outcomes and optimize healthcare resource utilization.